Columbia was spared a heavy buildup of ice that downed power lines in other parts of Missouri during the first wave of wintry weather this weekend.
You might say we were saved by the sleet.
The combination of arctic air near the surface and warmer temperatures higher in the atmosphere made forecasting precipitation types particularly tricky this weekend.
Benjamin Sipprell of the National Weather Service office in St. Louis said subfreezing air near the surface in the Columbia area extended far enough aloft on Friday during the day and at night to freeze most of the rain as it fell through the atmosphere and turn it into sleet before it reached the ground.
Rather than freezing and accumulating on trees and power lines, the sleet piled up on the ground. And while it made travel dangerous, it didn’t cause the widespread power outages that utilities feared.
Along and south of the Interstate 44 corridor, however, the arctic air was more shallow. In those places, the rain didn’t freeze until it reached trees, power lines and other surfaces near the ground. That’s why downed trees and power lines were widespread in the Springfield and St. Louis areas but not Columbia during the first phase of the weekend storm.
“St. Louis and the I-44 corridor is really the dividing line between the arctic air mass making a huge difference and creating freezing rain,” Sipprell said Saturday.
To illustrate the vertical profile of temperatures, Sipprell said, the temperature at 3,000 feet in Springfield at 5 a.m. Saturday was 46 degrees while the surface temperature was 28.
An ice storm warning remained in effect for the Columbia area until 6 a.m. Monday. Forecasters said the final wave of the three-tiered storm system could be as intense as the first and cause significant icing.
On Saturday afternoon, Sipprell said there was uncertainty about whether the wave of wintry precipitation expected to hit midday today through the afternoon will fall as freezing rain, sleet or a mixture.
In any event, Sipprell said, the precipitation should become all snow after midnight tonight before the storm moves out of the area and ushers in much colder conditions. Lows on Monday and Tuesday were forecast in the single digits.